Maintenance and Fatigue: A Way of Life

March 19, 2014
Studies reveal data that sleep deprivation is a cultural norm in the aviation maintenance workplace, although mechanics as a group are not generally cognizant of the fact that they do not get enough rest.

We in maintenance would be wise not to take fatigue in our workplace too lightly. Can you imagine calling your supervisor and saying, “I won’t be coming to work today, I am too tired?” Don’t be surprised if you hear, “Right, and don’t you be surprised if your paycheck looks a little tired.” 

The list of human factors that can affect aviation maintenance is broad, and is certainly not limited to fatigue. It encompasses a wide range of challenges that influence people very differently; maintenance professionals do not all share equal capabilities, strengths, weaknesses, or limitations. Unfortunately, in the sequence of events leading up to an airplane taking off for flight, aviation maintenance is one of the first places where the human errors can begin.

Aviation maintenance technicians often work long hours under pressure, including working through the night. This often results in not just extreme fatigue but errors, some of which may potentially be life threatening to pilots and passengers as well as to the AMT.

It is no secret that fatigue can come in different forms: physical, mental, and emotional. Physical fatigue can bring about muscle soreness, oxygen debt, or extreme tiredness caused by sleep deprivation, illness, or poor nutrition. Emotional fatigue resulting from performing undesirable tasks, sometimes under challenging conditions such as lack of proper tools, inadequate lighting, and meeting completion deadlines in terms of time, may affect the degree of high levels of focus and concentration associated with complex tasks and create mental fatigue. The mental fatigue combined with the physical or emotional, leads to increased errors and risks in safety sensitive arenas.

Fatigue-related accidents

There are a countless number of documented errors and accidents attributed to tiredness and fatigue in the maintenance workplace. Studies have shown that fatigue can have consequential effects on a person’s cognitive ability. Cognition refers to mental processes such as awareness, perception, reasoning, and judgment. Fatigue has drawn parallels to the effects of alcohol. In 2000, Williamson, Feyer, Friswell, and Finlay-Brown conducted a study on driver fatigue and found that after 17 to 19 hours without sleep, performance on some tests was equivalent or worse than that at 0.05 percent blood alcohol content. Response speeds were up to 50 percent slower for some tests and accuracy measures were significantly poorer at this level of alcohol. After longer periods without sleep, performance reached levels equivalent to the maximum alcohol dose given to participants (0.1 percent blood alcohol content). The findings reinforced empirically that sleep deprivation is likely to compromise decision-making ability and accuracy needed for safety on the road and in other industrial settings. (Abstract, Physical, Emotional and Mental Fatigue in the Aviation Environment,

Further FAA studies and self-reporting by aviation maintenance mechanics indicate the average sleep for aviation maintenance mechanics routinely to be five to six hours per night, two to three hours short of the required eight hours. Additional studies reveal data that sleep deprivation is a cultural norm in the aviation maintenance workplace, although mechanics as a group are not generally cognizant of the fact that they do not get enough rest.

Aviation accidents

One of the most notable aviation maintenance fatigue-related accidents occurred in 1990 when British Airways flight 5390 experienced a windscreen blowout shortly after departure. The left windscreen, which had been replaced prior to the flight, was blown out under the effects of the cabin pressure when it overcame the retention of the securing bolts. While the official accident report cited numerous contributing factors that led up to this incident, one of the most insidious was the effect of fatigue on the aircraft mechanic who conducted the task. The work was conducted very early in the morning at a time when the human body experiences a natural low, also known as circadian effect. This, combined with lack of sleep before his shift, may have contributed significantly to the aircraft mechanic’s perceptual judgmental error in selecting the wrong size bolts for the job and then justifying that decision by believing that the countersink was too big rather than the bolt was too small.

Air Midwest Flight 5481 crashed on take-off killing 21 people. The NTSB concluded that the aircraft was tail heavy and the pilot was unable to keep the nose down because elevator travel was restricted due to improperly rigged flight control cables. The NTSB reported the maintenance work to the aircraft’s elevator system was performed on the midnight shift in the early morning hours. Compounding the fatigue issues was the lengthy commute the employees made getting to the repair facility and long shifts that were routinely worked. Work had been performed on the elevator system and interviews with the mechanics indicated a number of shortcomings with maintenance procedures including lack of proper training, insufficient resources, and the possibility that fatigue affected the quality of the work performed.

How to enhance safety?

Education and training alone are most likely not enough to deter mechanics from working while fatigued when many organizations push their mechanics to work 14- to 16-hour days. A combination of pressures including customer satisfaction, management pressure, time pressures, along with interruption of revenue associated with the loss of use of an aircraft, seem to win out and over-ride good common sense as well as documented safety policy and procedures.  

So how do you not only cope with this problem but also further enhance safety?

• Be aware of and eliminate foods and snacks that provide quick energy. Eliminate sugar highs and crashes by eating a balanced diet.

• Avoid caffeine before bed and try not to go to bed too hungry or too full, as this interrupts and prevents deep solid rest.

• Exercise regularly, but not before bedtime as it increases energy levels.

• Coordinate your rest environment at home with family members to allow undisturbed sleep.

Healthy lifestyles do indeed make a positive difference but may not be enough. The cultural norm in the maintenance world, as well as aviation in general, is that no workday is too long. We intellectually realize that a lack of required rest periods is detrimental to safety, but as employers are we willing to consider other factors like staffing levels, and the availability of break periods, promises to customers, and the value of a dollar to increase safety margins in maintenance?

Effective fatigue risk management requires a partnership between the employer and the employee. Although unrealistic to aim for “zero fatigue” in all cases, an appropriate objective for fatigue risk management is to ensure that risks are as low as reasonably practical (Stewart & Holmes, 2008).

Opportunities exist in the maintenance environment to modify methods of task performance. Secondary inspections or operational and functional checks could provide the opportunity to “catch” and correct errors before they become a potential incident or accident. Scheduling the most safety-critical tasks, or those most susceptible to fatigue, at times when fatigue will have the least impact.

We would be foolish to think we can avoid the reduced mental functioning brought about by fatigue, but by bringing focus and awareness to it we can at least mitigate it. Whatever approach to fatigue we take, commitment from all levels in the organization is essential. Senior management should establish a clear policy on fatigue, which includes how issues will be dealt with in a just culture. Middle management should implement those policies, day to day. Ultimately, the quality of work rests with the individual maintenance technician. It is their responsibility and obligation by the maintenance creed they live by, to gain an understanding of the potential adverse consequences of fatigue and commit to employ any and all remedies to assure they remain well rested and able to perform tasks in a safe and effective manner.


• Federal Aviation Administration, Fatigue Risk Management in Aviation, (2011) 


• Aviation Today, May 2009

About the Author

DeborahAnn Cavalcante

DeborahAnn Cavalcante earned her Masters in Aeronautical Science, with a specialization in Safety Management from Embry Riddle Aeronautical University in Daytona, FL, and her Bachelor of Science from VA Tech in Business and Risk Management. 

DeborahAnn Cavalcante leads Diversified Aviation Consulting (DAC) and along with her associates has firsthand experience in air carrier operations, private charter aircraft, general aviation operations, military/civilian interface, FBO management, maintenance repair station training, safety training, human factors training, and customer service training. For more information on DAC visit